1. Field of the Invention
The present invention relates to an image forming apparatus and a method of controlling the same.
2. Description of the Related Art
Copying machines which are typical examples of image forming apparatuses are now widely used.
They are now used at various companies and offices, and are widely available to many peoples, for example at convenience stores, book stores, copy service stations and others.
Among copying machines which are now widely available, there are color copying machines provided with a function of forming color duplicate images.
With growing use of the color copying machines, various kinds of original images can now be color-copied without any difficulty. Under these circumstances, such a problem has arisen that bills, securities, postcards, postage stamps, copyrighted materials and others can be erroneously copied. In particular, it is generally less recognized that copyrighted materials cannot be color-copied. As an example of measures for prohibiting duplication of copy-protected materials, such a technique has been known that the copying machine has a bill determining function of automatically determining whether an original is a bill or not, and can disable a copying operation if the original is a bill. However, it is difficult to determine various kinds of copy-protected materials only by this kind of technique, and color-copying of a copy-protected original may be erroneously performed. In view of this, it is desired to request an operator to ascertain the original, to ascertain copied documents by a manager of the copying machine or the like, or to request an operator not to duplicate a color-copy-protected original.
With increase in number of generally available color copying machines having a function of forming a full-color duplicate image, users which are not used to operate the color copying machines are now increasing in number. Compared with general monochrome copying machines, the color copying machines have more functions such as color balance control which require more experience for setting and controlling them. Setting operations for these functions take a long time, and thus the color copying operation may take an excessively long time. Particularly, if the operator is not used to the operation of the color copying machine, the operation takes an extremely long time, and further many erroneously copied documents may be produced due to an erroneous operation. In the worst case, an operator cannot produce an intended duplicate even after repeating the copying operation many times. In this case, the operator needs a help by an expert such as a manager of the copying machine who is an expert in copying operation so that the operator can perform the color copying in a short time without producing many erroneous duplicates owing to an advice and an instruction by the expert.